We seem to do a reasonable job of measuring the sound field for the recordings that people like to wax lyrical about, and that simply requires a pressure sensor

Floyd Toole, has a 72 point anechoic measurement system, which measures around the speaker, and  captures some of the dispersion charcteristic. He also has a computer simulation which takes that data and calculates what it will meaure like in a room. And having hugely expensive test facilities to play with, they even measure the speaker in a real room and get a fair correspondence of measured and simulated in room response, validating their simulation technique.  Anyone with $20M or so for R&D could do it!

 

There are just so many interesting speakers, which have vastly different in room responses, that it's just not worth wasting time (or money) agonizing over +/- 0.1dB variations in CD players. It's why I think it makes perfect sense to spend $250 on a sony CD player and to put as much money as possible into the speakers...